Something oozing out if thimble

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sowers25

Member
Jan 16, 2012
70
NE West Virginia
I got home from work and found a blackish wet lookin stain coming down my brick profile from the bottom I my thimble. Anyone have any idea what it is and what's causing it?
 

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Have you recently had wind and rain? If so it appears that you have had water intrusion. Only other culprit is creosote. Slow dirty burns.
 
Looks like glazed creosote that has turned to liquid creosote.

If i saw that my stove would get shut down and the pipe would come off to be checked.
 
I second the water in the chimney and washing creosote down into the house.
 
I second the water in the chimney and washing creosote down into the house.
Is that horizontal pipe section level, or at least sloped in the right direction? It's hard to tell from the pic, but it looks like it might be just slightly sloped. Sure looks like rain washed creosote or just soot to me. Even a relatively clean chimney might easily have just enough black stuff to get washed down and leak out the stovepipe, but as I understand, the pipe connections should be such that any water should not be able to leak out the connections unless there is a place for water to accumulate
 
What do you have for a stove and how new are you to burning? Is this your first season? Do you have a temp guage on it anyplace? Any idea how clean you are burning?

I think it's creasote from a not hot enough burn and/or with less than fully seasoned wood.
 
What do you have for a stove and how new are you to burning? Is this your first season? Do you have a temp guage on it anyplace? Any idea how clean you are burning?

I think it's creasote from a not hot enough burn and/or with less than fully seasoned wood.


I have a 30 nc just got it up and running a few weeks ago. Yes it's my first year burning, my wood is mostly oak dead standing but will admit its probably got a little too much moisture in it. Just measured a fresh split with a mm and its reading around 26-28. The stove temp has been at least 350, having a hard time getting it to the higher ranges, probably on account of my wood.
 
26% is pretty good! I think you may not have enough draft?

As far as the slopped chimney that makes sense that it should slope out so water dont run in, but can we confirm that his is that way??
 
The stove temp has been at least 350, having a hard time getting it to the higher ranges, probably on account of my wood.

RED FLAG. That stove should hit 600 without even trying. If you cannot get above 350F - you have a problem. First glance says wood!
 
RED FLAG. That stove should hit 600 without even trying. If you cannot get above 350F - you have a problem. First glance says wood!
NC 30's are usually referred to as "heat dragons" around here. Do have a smoke problem? Dirty glass? Sounds like wood, or draft, or air supply problem? Does the fire flare up when you open the door (suggesting an air supply issue maybe)? Could there be a flue draft control that's closed?
 
NC 30's are usually referred to as "heat dragons" around here. Do have a smoke problem? Dirty glass? Sounds like wood, or draft, or air supply problem? Does the fire flare up when you open the door (suggesting an air supply issue maybe)? Could there be a flue draft control that's closed?

No smoke problem as far as smoke bellowing out when I open the door. The glass does get dirty at the end o a burn, like when I get up in the morning after a all night burn, but clears up once I get it up and going again good. The fire does flare up when I first open the door to reload, but isn't that normal? All the drafts controls are open and working in proper order. I believe it's the wood because I have gotten it up to 500-600 on a few occasions with really good looking wood. All the wood I have is pretty fresh splits so it hasn't had a lot of time to air out
 
What type of temps do you get on the pipe? If stack temps don't get past 320F you have a creosote factory. Oak takes a long time to get it below 20% moisture content.
 
No smoke problem as far as smoke bellowing out when I open the door. The glass does get dirty at the end o a burn, like when I get up in the morning after a all night burn, but clears up once I get it up and going again good. The fire does flare up when I first open the door to reload, but isn't that normal? All the drafts controls are open and working in proper order. I believe it's the wood because I have gotten it up to 500-600 on a few occasions with really good looking wood. All the wood I have is pretty fresh splits so it hasn't had a lot of time to air out
Unless somebody else has some other ideas, it sounds like the wood, and it probably is causing a lot of creosote. But you also have the problem of water leaking it sounds like. You have to track that down, maybe by taking some sections out of the stovepipe. Did you determine yet if there is a place in there where water could be accumulating? It really shouldn't be leaking. There are some people here very knowledgeable about pipes and chimneys.
 
26% is pretty good! I think you may not have enough draft?

As far as the slopped chimney that makes sense that it should slope out so water dont run in, but can we confirm that his is that way??
Thats too wet.
 
Your wood is higher for a EPA stove, but also what size is your flue? These stoves aren't like the old ones that put alot of heat up the chimney. If the flue is too large, the gasses can condense and what your seeing will occur. We had it happen to us, and drier wood and a chimney liner solved all our problems.
 
Unless somebody else has some other ideas, it sounds like the wood, and it probably is causing a lot of creosote. But you also have the problem of water leaking it sounds like. You have to track that down, maybe by taking some sections out of the stovepipe. Did you determine yet if there is a place in there where water could be accumulating? It really shouldn't be leaking. There are some people here very knowledgeable about pipes and chimneys.
The flue is 6" inside going to a 8x8 masonary on outside of house with a cap on top it hasn't rained here lately though unless hurricane sandy left some water in there somehow but I don't see how that could be considering I've burnt it a lot since then and it surely would evaporate. So I can't see how it could be water. When we put the black stove pipe through the wall I never sealed it with anything, should have I?
 
When we put the black stove pipe through the wall I never sealed it with anything, should have I?

Well....maybe, BUT it might have been a good thing that you didn't. Something needs to change. Obviously the fuel supply is suspect, but dumping into an 8 x 8 outside flue is going to AMPLIFY this problem.
 
I know its not what you want to burn but it will burn and get Way hotter than that. I know!
Yea if he knows what he is dealing with, now he doesn't want a hot fire due to the creosote, time to start over and clean the chimney and try some dryer wood and see what happens.
 
Your wood is higher for a EPA stove, but also what size is your flue? These stoves aren't like the old ones that put alot of heat up the chimney. If the flue is too large, the gasses can condense and what your seeing will occur. We had it happen to us, and drier wood and a chimney liner solved all our problems.
Good point. If it's not water, then it's liquidy creosote. Here's a good article on that subject and how best to take care of it. http://www.chimneysweeponline.com/hoburnout.htm

I believe that creosote starts out as a liquid condensate, then hardens over time. However, that still doesn't explain how it's getting out. The pipe sections should be nested so that liquid can't drip out.
 
The pipe sections should be nested so that liquid can't drip out.
the pipe is stubbed into the 8 x 8. Stuff drips down the walls of the 8x8 hits the horizontal run and then drips in behind the thimble wall plate. Ooey gooey mess.
 
the pipe is stubbed into the 8 x 8. Stuff drips down the walls of the 8x8 hits the horizontal run and then drips in behind the thimble wall plate. Ooey gooey mess.
There you go. Sounds right. It might also be some condensed water dripping down after the water vapor from the fire cools in the 8x8. Others here are much more expert on flues, but you might have to consider lining the masonry flue.

As for the wood, if you can't get truly dry wood now, it might help to use some biobricks or similar pressed log product. Some people burn them along with less than desireable wood. The idea is to get the whole load closer to 20% or less. I've never tried it myself, but it has been suggested here.
 
Sounds i like your wood is to wet combined with your chimney.
 
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